I filled up yesterday, which was so far the hottest day of the year here (Wisconsin), and when I got home and parked, my bike started leaking gas. It looked like the gas was come out of the carb drain screw, but I verified it was tight, so maybe it was just pushing out the carb bowl gaskets? Not sure, either way, what the?
My thoughts are that with the heat (about 90 degrees and 90% humidity) that the fuel in my totally full tank expanded, and/or the fuel in the carb bowls expanded too much and the pressure caused it to overflow. The bike was running fine when I parked it, I then waited a couple hours and it ran just great after that, I took it out a couple times last night and it never leaked gas again. Has anyone else had that happen to them or heard of it?
Ah man, that's crazy! I have never experienced that... and it has gotten pretty hot around here too.
I've gotta put gas in my bike later today too actually... flipped to reserve omw home from work last night.
Curious for other people to reply with their thoughts... but I'm glad to know it has stopped for you!
It certainly shouldn't have expanded enough to leak..... I mean, the gas tank and the carbs are both vented, so there shouldn't be any pressure build up. And I can't imagine there was enough liquid gas to expand SO much to cause a leak (just not enough mass if that makes sense.....).
Either way, keep an eye on it. It might be a good idea to check your vent systems to be on the safe side.
I saw a doco on the SR-71 and when it was filled before a mission the fuel would pour out from the numerous leaks in the the aircraft as it did not fully seal until it reached operating temperature and everything expanded into place. To see one of those blackbirds on the tarmac with aviation fuel copiously leaking out is an awesome sight.
dang! maybe i'm riding a GS-Blackbird :D
I'll keep an eye on it, thought it was super odd. There was a pretty decent sized puddle under the bike. I was dealing with a fuel leak before and this was totally different than my last one. Hopefully it was just an oddball one time deal. Bike seems to be riding great.
Your cap-vent might be clogged or otherwise not venting. The previous owner of mine put on a non-stock filler cap, and I don't think it vents terribly well; I have the same symptoms. Under the bike it'll piss a little bit of fuel on full fill up, and it would appear to be right under the carbs. I think it's just expansion-purging somewhere like one of the carb vents or something. I wouldn't worry about it too much unless it gets excessive, or you see it actually puddling. In the meantime, verify your venting is working, the gas cap is clean and the vent around it is good, etc.
Definitely just seems like a venting issue.
Quote from: chornbe on July 22, 2016, 06:10:20 AM
Your cap-vent might be clogged or otherwise not venting. The previous owner of mine put on a non-stock filler cap, and I don't think it vents terribly well; I have the same symptoms. Under the bike it'll piss a little bit of fuel on full fill up, and it would appear to be right under the carbs. I think it's just expansion-purging somewhere like one of the carb vents or something. I wouldn't worry about it too much unless it gets excessive, or you see it actually puddling. In the meantime, verify your venting is working, the gas cap is clean and the vent around it is good, etc.
Definitely just seems like a venting issue.
cool, thanks for the information. i'll definitely check into that. my symptoms sound just like what you explained